You have to ask these questions to someone who is an expert in the topic. Maybe try to do some research online.
I didn’t understand your first question – Was he originally addicted to drugs, to alcohol or both?
Also – I’m not sure that I would consider Shabbos, simchas, sometimes wine with dinner to be regular drinking. How much is he drinking at a time? And how often are the simchas/wine with dinner? Does he get tipsy or drunk or is he fine with the amount he is drinking?
I was under the impression that there is nothing wrong with a glass of wine a day, but I might be wrong (definitely not my area of expertise). This had been discussed on another thread. Or is the issue that he used to be alcoholic, and you are afraid that this “regular drinking” will cause him to revert? You would have to find out if a recovered alcoholic is better off drinking in controlled moderate amounts or abstaining altogether.